Mechanism for dispensing liquid onto an integrated circuit wafer with minimized back-splash

ABSTRACT

A mechanism for effectively dispensing liquid onto a surface of an IC (Integrated Circuit) wafer with minimized back-splash. A nozzle includes a liquid chamber that fills up with the liquid to be dispensed onto the surface of the IC wafer, and the nozzle includes a plurality of nozzle passages. A nozzle passage carries and directs the liquid from the liquid chamber toward the surface of the IC wafer to provide a respective liquid stream from a respective location on the nozzle to a respective spot on the surface of the IC wafer as the IC wafer is spinning. A nozzle passage is disposed within the nozzle at a respective angle with respect to the surface of the IC wafer such that the respective liquid stream from the nozzle passage is directed toward a velocity vector at the respective spot on the surface of the IC wafer where the respective liquid stream hits the surface of the IC wafer. For example, the respective angle of the nozzle passage with respect to the surface of the IC wafer may be 45°. The angling of the liquid stream toward the velocity vector on the IC wafer as the IC wafer spins reduces back-splash when the liquid stream hits the IC wafer. In addition, the liquid stream may be applied onto the surface of the IC wafer with relatively low pressure. Thus, the nozzle of the present invention dispenses liquid onto the surface of the IC wafer with minimized back-splash to reduce bubble defects within the integrated circuit fabricated on the surface of the IC wafer.

This is a divisional of an earlier filed patent application, with Ser.No. 09/390,934 filed on Sep. 7, 1999, now U.S. Pat. No. 6,238,747, forwhich priority is claimed. This earlier filed patent application withSer. No. 09/390,934 is in its entirety incorporated herewith byreference.

TECHNICAL FIELD

The present invention relates generally to IC (Integrated Circuit) waferfabrication systems, and more particularly, to a mechanism fordispensing liquid onto the IC wafer with minimized back-splash to reducebubble defects during fabrication of integrated circuits on the ICwafers.

BACKGROUND OF THE INVENTION

Referring to FIG. 1, liquid such as solution used for fabrication ofintegrated circuits on an IC (Integrated Circuit) wafer 102 is dispensedfrom a nozzle 104 of the prior art onto a surface 103 of the IC wafer102 as the IC wafer 102 spins. FIG. 1 shows a top view of the nozzle 104placed across the diameter of the surface 103 of the IC wafer 102. FIG.2 shows a side view of the nozzle 104 that is placed across the diameterof the surface 103 of the IC wafer 102 of FIG. 1. Elements having thesame reference number in FIGS. 1 and 2 refer to elements having similarstructure and function.

Referring to FIGS. 1 and 2, the nozzle 104 of the prior art includes aliquid chamber 106 that fills up with the liquid to be dispensed ontothe surface 103 of the IC wafer 102. In addition, the nozzle 104 of theprior art includes a plurality of nozzle passages that carry and directthe liquid from the liquid chamber 106 onto the surface 103 of the ICwafer 102. The nozzle 104 includes a first nozzle passage 112, a secondnozzle passage 114, a third nozzle passage 116, a fourth nozzle passage118, a fifth nozzle passage 120, a sixth nozzle passage 122, and aseventh nozzle passage 124. (Note that the plurality of nozzle passages112, 114, 116, 118, 120, 122, and 124 in FIGS. 1 and 2 are shown to berelatively large for clarity of illustration. However, a typical size ofthe each of the nozzle passages 112, 114, 116, 118, 120, 122, and 124 isapproximately 0.5 millimeters).

These plurality of nozzle passages 112, 114, 116, 118, 120, 122, and 124in the nozzle 104 of the prior art are directed vertically downward tobe perpendicular to the surface 103 of the IC wafer 102. Each of thesenozzle passages 112, 114, 116, 118, 120, 122, and 124 in the nozzle 104of the prior art directs a respective liquid stream of the liquid fromthe liquid chamber 106 toward the surface 103 of the IC wafer 102 as theIC wafer 102 spins (for example in the clockwise direction asillustrated in FIGS. 1 and 2).

Thus, the first nozzle passage 112 carries and directs a first liquidstream 113 from the liquid chamber 106 toward the surface 103 of the ICwafer 102. Similarly, the second nozzle passage 114 carries and directsa second liquid stream 115 from the liquid chamber 106 toward thesurface 103 of the IC wafer 102. The third nozzle passage 116 carriesand directs a third liquid stream 117 from the liquid chamber 106 towardthe surface 103 of the IC wafer 102. The fourth nozzle passage 118carries and directs a fourth liquid stream 119 from the liquid chamber106 toward the surface 103 of the IC wafer 102. The fifth nozzle passage120 carries and directs a fifth liquid stream 121 from the liquidchamber 106 toward the surface 103 of the IC wafer 102. The sixth nozzlepassage 122 carries and directs a sixth liquid stream 123 from theliquid chamber 106 toward the surface 103 of the IC wafer 102. Theseventh nozzle passage 124 carries and directs a seventh liquid stream125 from the liquid chamber 106 toward the surface 103 of the IC wafer102.

In the prior art, each of these liquid streams 113, 115, 117, 119, 121,123, and 125 is directed vertically downward to be perpendicular to thesurface 103 of the IC wafer 102 as the IC wafer 102 spins. In addition,in the prior art, each of these liquid streams 113, 115, 117, 119, 121,123, and 125 is typically dispensed aggressively onto the surface 103 ofthe IC wafer 102 with much pressure.

Unfortunately in the prior art, a relatively large amount of back-splashof liquid dispensed onto the surface 103 of the IC wafer 102 results.Referring to FIG. 2, a layer of liquid 130 is dispensed onto the surface103 of the IC wafer 102 from the nozzle of the prior art 104. Thesurface 103 of the wafer 102 may have a layer of another materialalready deposited thereon. For example, the surface 103 of the wafer 102may have a layer of photoresist 132 deposited thereon, and the layer ofliquid 130 dispensed onto the IC wafer 102 may be developer solution fordeveloping the layer of photoresist 132.

Referring to FIG. 2, as the liquid streams 113, 115, 117, 119, 121, 123,and 125 are aggressively directed vertically downward toward the ICwafer 102 to be perpendicular to the surface 103 of the IC wafer 102,back-splash of the liquid from the layer of liquid 130 on the IC wafer102 results. With such back-splash, the liquid from the layer of liquid130 bounce back up and away from the IC wafer 102, and bubbles formwithin the layer of liquid 130 on the IC wafer 102. Examples of suchbubbles 140, 142, 144, and 146 are shown in FIG. 2 within the layer ofliquid 130 on the IC wafer 102.

Such bubbles 140, 142, 144, and 146 are more prone to form with thenozzle 104 of the prior art because the liquid streams are directedtoward the IC wafer 102 with relatively high pressure. In addition, suchbubbles 140, 142, 144, and 146 are more prone to form with the nozzle104 of the prior art because the liquid streams are directed verticallydownward toward the IC wafer 102 to be perpendicular to the surface 103of the IC wafer 102 as the IC wafer 102 is spinning. The velocity of theIC wafer 102 as the IC wafer 102 is spinning creates a force against aliquid stream when the liquid stream contacts the IC wafer 102, and suchforce contributes to the back-splash of the liquid when the liquidstream contacts the layer of liquid 130.

A bubble is located at a respective location within the layer of liquid130 directly above the IC wafer 102, and such a bubble causes thatrespective location of the IC wafer 102 to be exposed to a low volume ofliquid of the layer of liquid 130. However, proper exposure of the ICwafer 102 to a sufficient amount of liquid of the layer of liquid 130dispensed onto the wafer 102 is desired for proper fabrication ofintegrated circuit structures on the IC wafer 102. With a bubble withinthe layer of liquid 130, the respective location of the IC wafer 102having the bubble thereon may not be exposed to a sufficient volume ofliquid of the layer of liquid 130. Such insufficient volume of liquid ofthe layer of liquid 130 at that location of the IC wafer 102 results inan integrated circuit defect at that location of the IC wafer 102, andsuch an integrated circuit defect may be referred to as a “bubbledefect.”

Furthermore, a long-recognized important objective in the constantadvancement of monolithic IC (Integrated Circuit) technology is thescaling-down of IC dimensions. Such scaling-down of IC dimensionsreduces area capacitance and is critical to obtaining higher speedperformance of integrated circuits. Moreover, reducing the area of an ICdie leads to higher yield in IC fabrication. Such advantages are adriving force to constantly scale down IC dimensions. Referring to FIG.2, as IC dimensions are further scaled down to submicron and nanometerdimensions, a bubble formed within the layer of liquid 130 is morelikely to cause defects within integrated circuit structures with suchscaled down dimensions on the IC wafer 102.

Thus, to generally minimize defects within integrated circuits on the ICwafer 102, and further in light of the importance of scaling down ICdimensions, a mechanism is desired for effectively dispensing liquidonto the IC wafer with minimized back-splash to reduce bubble defectsduring fabrication of integrated circuits on the IC wafers.

SUMMARY OF THE INVENTION

Accordingly, a general aspect of the present invention includes a nozzleapparatus and method for effectively dispensing liquid onto a surface ofan IC (Integrated Circuit) wafer with minimized back-splash.

In one embodiment of the present invention, a nozzle includes a liquidchamber that fills up with the liquid to be dispensed onto the surfaceof the IC wafer, and the nozzle includes a plurality of nozzle passages.A nozzle passage carries and directs the liquid from the liquid chambertoward the surface of the IC wafer to provide a respective liquid streamfrom a respective location on the nozzle to a respective spot on thesurface of the IC wafer as the IC wafer is spinning. In addition,according to a general aspect of the present invention, a nozzle passageis disposed within the nozzle at a respective angle with respect to thesurface of the IC wafer such that the respective liquid stream from thenozzle passage is directed toward a velocity vector at the respectivespot on the surface of the IC wafer where the respective liquid streamhits the surface of the IC wafer. For example, the respective angle ofthe nozzle passage with respect to the surface of the IC wafer may be45°. In addition, the liquid stream is dispensed onto the surface of theIC wafer with relatively low pressure according to another aspect of thepresent invention.

The present invention may be used to particular advantage when theliquid is developer solution dispensed on the surface of the IC waferfor developing photoresist deposited on the surface of the IC wafer.

In this manner, the nozzle of the present invention dispenses liquidonto the surface of the IC wafer with minimized back-splash to reducebubble defects within the integrated circuit fabricated on the surfaceof the IC wafer. The angling of the liquid stream toward the velocityvector on the IC wafer as the IC wafer spins reduces back-splash whenthe liquid stream hits the IC wafer. In addition, the liquid stream isapplied onto the surface of the IC wafer with relatively low pressure.

These and other features and advantages of the present invention will bebetter understood by considering the following detailed description ofthe invention which is presented with the attached drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 shows a top view of a prior art nozzle used for dispensing liquidonto an IC (Integrated Circuit) wafer;

FIG. 2 shows a side view of the prior art nozzle of FIG. 1 in operationfor dispensing liquid onto the IC wafer of FIG. 1;

FIG. 3 shows a top view of a nozzle having angled nozzle passages usedfor dispensing liquid onto an IC (Integrated Circuit) wafer withminimized back-splash when the IC wafer is spinning in the clockwisedirection, according to an embodiment of the present invention;

FIG. 4 shows a side view from the south side of the nozzle of FIG. 3 inoperation for dispensing liquid onto the IC wafer at an angle tominimize back-splash when the IC wafer is spinning in the clockwisedirection, according to an embodiment of the present invention;

FIG. 5 shows a side view from the east side of the nozzle of FIG. 3 inoperation for dispensing liquid onto the IC wafer at an angle tominimize back-splash when the IC wafer is spinning in the clockwisedirection, according to an embodiment of the present invention;

FIG. 6 shows a side view from the west side of the nozzle of FIG. 3 inoperation for dispensing liquid onto the IC wafer at an angle tominimize back-splash when the IC wafer is spinning in the clockwisedirection, according to an embodiment of the present invention;

FIG. 7 shows a top view of a nozzle having angled nozzle passages usedfor dispensing liquid onto an IC (Integrated Circuit) wafer withminimized back-splash when the IC wafer is spinning in thecounter-clockwise direction, according to an embodiment of the presentinvention;

FIG. 8 shows a side view from the east side of the nozzle of FIG. 7 inoperation for dispensing liquid onto the IC wafer at an angle tominimize back-splash when the IC wafer is spinning in thecounter-clockwise direction, according to an embodiment of the presentinvention; and

FIG. 9 shows a side view from the west side of the nozzle of FIG. 7 inoperation for dispensing liquid onto the IC wafer at an angle tominimize back-splash when the IC wafer is spinning in thecounter-clockwise direction, according to an embodiment of the presentinvention.

The figures referred to herein are drawn for clarity of illustration andare not necessarily drawn to scale. For example the nozzle passagesFIGS. 1, 2, 3, 4, 5, 6, 7, 8, and 9 are shown to be relatively large forclarity of illustration. However, a typical size of each of such nozzlepassages is approximately 0.5 millimeters. Elements having the samereference number in FIGS. 1, 2, 3, 4, 5, 6, 7, 8, and 9 refer toelements having similar structure and function.

DETAILED DESCRIPTION

Referring to FIG. 3, liquid such as solution used for fabrication ofintegrated circuits on an IC (Integrated Circuit) wafer 202 is dispensedfrom a nozzle 204 of an embodiment of the present invention onto asurface 203 of the IC wafer 202 as the IC wafer 202 spins. FIG. 3 showsa top view of the nozzle 204 placed across the diameter of the surface203 of the IC wafer 202. FIG. 4 shows a side view from the southdirection of the nozzle 204 that is placed across the diameter of thesurface 203 of the IC wafer 202 of FIG. 3.

Referring to FIGS. 3 and 4, the nozzle 204 of an embodiment of thepresent invention includes a liquid chamber 206 that fills up with theliquid to be dispensed onto the surface 203 of the IC wafer 202. Inaddition, the nozzle 204 of an embodiment of the present inventionincludes a plurality of nozzle passages that carry and direct the liquidfrom the liquid chamber 206 onto the surface 203 of the IC wafer 202.The nozzle 204 includes a first nozzle passage 212, a second nozzlepassage 214, a third nozzle passage 216, a fourth nozzle passage 218, afifth nozzle passage 220, a sixth nozzle passage 222, and a seventhnozzle passage 224.

In contrast to the prior art, each of these plurality of nozzle passages212, 214, 216, 218, 220, 222, and 224 in the nozzle 204 of an embodimentof the present invention are directed downward at an angle with respectto the surface 203 of the IC wafer 202 as the IC wafer 202 spins. Eachof the nozzle passages 212, 214, 216, 218, 220, 222, and 224 in thenozzle 204 carries and directs a respective liquid stream of the liquidfrom the liquid chamber 206 toward the surface 203 of the IC wafer 202as the IC wafer 202 spins (for example in the clockwise direction asillustrated in FIGS. 3 and 4).

Thus, the first nozzle passage 212 carries and directs a first liquidstream 213 from the liquid chamber 206 toward the surface 203 of the ICwafer 202. Similarly, the second nozzle passage 214 carries and directsa second liquid stream 215 from the liquid chamber 206 toward thesurface 203 of the IC wafer 202. The third nozzle passage 216 carriesand directs a third liquid stream 217 from the liquid chamber 206 towardthe surface 203 of the IC wafer 202. The fourth nozzle passage 218carries and directs a fourth liquid stream 219 from the liquid chamber206 toward the surface 203 of the IC wafer 202. The fifth nozzle passage220 carries and directs a fifth liquid stream 221 from the liquidchamber 206 toward the surface 203 of the IC wafer 202. The sixth nozzlepassage 222 carries and directs a sixth liquid stream 223 from theliquid chamber 206 toward the surface 203 of the IC wafer 202. Theseventh nozzle passage 224 carries and directs a seventh liquid stream225 from the liquid chamber 206 toward the surface 203 of the IC wafer202.

The respective liquid stream from each of the nozzle passages 212, 214,216, 218, 220, 222, and 224 in the nozzle 204 is from a respectivelocation on the nozzle to a respective spot on the surface 203 of the ICwafer 202 as the IC wafer 202 spins. Each of the nozzle passages 212,214, 216, 218, 220, 222, and 224 in the nozzle 204 is disposed withinthe nozzle 204 at a respective angle with respect to the surface 203 ofthe IC wafer 202 such that the respective liquid stream from the nozzlepassage is directed toward a velocity vector at the respective spot onthe surface 203 of the IC wafer 202 where the respective liquid streamhits the surface 203 of the IC wafer 202.

Referring to FIGS. 3 and 4 for example, each of the plurality of nozzlepassages 212, 214, 216, 218, 220, 222, and 224 in the nozzle 204 arealigned in a linear configuration to face the surface 203 of the ICwafer 202 across a diameter of the IC wafer 202. If the IC wafer 202were spinning in a clockwise direction (as illustrated in FIGS. 3 and4), then the velocity vector at spots of the IC wafer 202 to the left ofa center line 230 of the IC wafer 202 is in the north direction, and thevelocity vector at spots of the IC wafer 202 to the right of the centerline 230 of the IC wafer 202 is in the south direction.

Thus, a first plurality of nozzle passages including the first nozzlepassage 212, the second nozzle passage 214, and the third nozzle passage216 which are aligned in the linear configuration to the left of thecenter line 230 of the IC wafer 202 are angled toward the northdirection to provide a respective liquid stream angled toward the northdirection. Similarly, a second plurality of nozzle passages includingthe fifth nozzle passage 220, the sixth nozzle passage 222, and theseventh nozzle passage 224 which are aligned in the linear configurationto the right of the center line 230 of the IC wafer 202 are angledtoward the south direction to provide a respective liquid stream angledtoward the south direction.

The fourth nozzle passage 218 is a center nozzle passage disposedbetween the first plurality of nozzle passages 212, 214, and 216 and thesecond plurality of nozzle passages 220, 222, and 224. The fourth nozzlepassage 218 is directed toward a center of the surface 203 of the ICwafer 202. A velocity vector does not exist at the center of the surface203 of the IC wafer 202 since the IC wafer 202 spins about such acenter. Thus, the fourth nozzle passage 218 is directed verticallydownward to be perpendicular to the surface 203 of the IC wafer 202.

Thus, referring to FIG. 4 which shows a side view from the south side ofthe nozzle 204 of FIG. 3, the first liquid stream 213, the second liquidstream 215, and the third liquid stream 217 face inward (toward thepaper and away from the reader). On the other hand, the fifth liquidstream 220, the sixth liquid stream 222, and the seventh liquid stream224 face outward (away from the paper and toward the reader). The fourthliquid stream 219 is directed vertically downward to be perpendicular tothe surface 203 of the IC wafer 202.

For further illustration of such angling of the nozzle passages and therespective liquid streams, FIG. 5 shows a side view from the east sideof the nozzle 204 of FIG. 3. Referring to FIGS. 3 and 5, the IC wafer202 is spinning in the clockwise direction, and from the east side viewof FIG. 3, the wafer 202 is spinning toward the left (i.e. toward thesouth direction). Thus, the velocity vector at spots toward the right(i.e. toward the east) of the center line 230 of the IC wafer 202 isdirected toward the south direction. Thus, the seventh nozzle passage224 (similar to the fifth nozzle passage 220 and the sixth nozzlepassage 222) which is disposed to the right of the center line 230 isalso angled toward the left (i.e. toward the south direction) which isalso toward the velocity vector at spots toward the right (i.e. towardthe east) of the center line 230 of the IC wafer 202.

Referring to FIG. 5, the seventh nozzle passage 224 (along with therespective seventh liquid stream 225) may be directed at an angle ofθ=45° for example with respect to the surface 203 of the IC wafer 202.Similarly, the fifth nozzle passage 220 and the sixth nozzle passage 222may also be directed at an angle of θ=45° for example with respect tothe surface 203 of the IC wafer 202.

On the other hand, FIG. 6 shows a side view from the west side of thenozzle 204 of FIG. 3. Referring to FIGS. 3 and 6, the IC wafer 202 isspinning in the clockwise direction, and from the west side view of FIG.3, the wafer 202 is spinning toward the left (i.e. toward the northdirection). Thus, the velocity vector at spots toward the left (i.e.toward the west) of the center line 230 of the IC wafer 202 is directedtoward the north direction. Thus, the first nozzle passage 212 (similarto the second nozzle passage 214 and the third nozzle passage 216) whichis disposed to the left of the center line 230 is also angled toward theleft (i.e. toward the north direction) which is also toward the velocityvector at spots toward the left (i.e. toward the west) of the centerline 230 of the IC wafer 202.

Referring to FIG. 6, the first nozzle passage 212 (along with therespective first stream 213) may be directed at an angle of θ=45° forexample with respect to the surface 203 of the IC wafer 202. Similarly,the second nozzle passage 214 and the third nozzle passage 216 may alsobe directed at an angle of θ=45° for example with respect to the surface203 of the IC wafer 202.

Alternatively, referring to FIG. 7, if the IC wafer 202 were spinning inthe counter-clockwise direction, then the velocity vector at spots ofthe IC wafer 202 to the left of the center line 230 of the IC wafer 202is in the south direction, and the velocity vector at spots of the ICwafer 202 to the right of the center line 230 of the IC wafer 202 is inthe north direction. Thus, the first plurality of nozzle passagesincluding the first nozzle passage 212, the second nozzle passage 214,and the third nozzle passage 216 which are aligned in the linearconfiguration to the left of the center line 230 of the IC wafer 202 areangled toward the south direction to provide a respective liquid streamangled toward the south direction. Similarly, the second plurality ofnozzle passages including the fifth nozzle passage 220, the sixth nozzlepassage 222, and the seventh nozzle passage 224 which are aligned in thelinear configuration to the right of the center line 230 of the IC wafer202 are angled toward the north direction to provide a respective liquidstream angled toward the north direction. The fourth nozzle passage 218,which is directed toward the center of the surface 203 of the IC wafer202, is directed vertically downward to be perpendicular to the surface203 of the IC wafer 202.

FIG. 8 shows a side view from the east side of the nozzle 204 of FIG. 7.Referring to FIGS. 7 and 8, the IC wafer 202 is spinning in thecounter-clockwise direction, and from the east side view of FIG. 7, thewafer 202 is spinning toward the right (i.e. toward the northdirection). Thus, the velocity vector at spots toward the right (i.e.toward the east) of the center line 230 of the IC wafer 202 is directedtoward the north direction. Thus, the seventh nozzle passage 224(similar to the fifth nozzle passage 220 and the sixth nozzle passage222) which is disposed to the right of the center line 230 is alsoangled toward the right (i.e. toward the north direction) which is alsotoward the velocity vector at spots toward the right (i.e. toward theeast) of the center line 230 of the IC wafer 202.

Referring to FIG. 8, the seventh nozzle passage 224 (along with therespective seventh liquid stream 225) may be directed at an angle ofθ=45° for example with respect to the surface 203 of the IC wafer 202.Similarly, the fifth nozzle passage 220 and the sixth nozzle passage 222may also be directed at an angle of θ=45° for example with respect tothe surface 203 of the IC wafer 202.

On the other hand, FIG. 9 shows a side view from the west side of thenozzle 204 of FIG. 7. Referring to FIGS. 7 and 9, the IC wafer 202 isspinning in the counter-clockwise direction, and from the west side viewof FIG. 7, the wafer 202 is spinning toward the right (i.e. toward thesouth direction). Thus, the velocity vector at spots toward the left(i.e. toward the west) of the center line 230 of the IC wafer 202 isdirected toward the south direction. Thus, the first nozzle passage 212(similar to the second nozzle passage 214 and the third nozzle passage216) which is disposed to the left of the center line 230 is also angledtoward the right (i.e. toward the south direction) which is also towardthe velocity vector at spots toward the left (i.e. toward the west) ofthe center line 230 of the IC wafer 202.

Referring to FIG. 9, the first nozzle passage 212 (along with therespective first stream 213) may be directed at an angle of θ=45° forexample with respect to the surface 203 of the IC wafer 202. Similarly,the second nozzle passage 214 and the third nozzle passage 216 may alsobe directed at an angle of θ=45° for example with respect to the surface203 of the IC wafer 202.

In this manner, referring to FIG. 4, the angling of the liquid streamstoward the velocity vector on the IC wafer 202, as the IC wafer 202spins, reduces back-splash when the liquid streams hit a layer of liquid250 that is dispensed onto the surface 203 of the IC wafer 202 from thenozzle 204. Thus, bubble formation is minimized within the layer ofliquid 250 to reduce bubble defects within the integrated circuitfabricated on the surface 203 of the IC wafer 202. For example, thelayer of liquid 250 may be developer solution for developing a layer ofphotoresist 252 deposited on the surface 203 of the IC wafer 202. Withsuch minimization of bubble formation within the layer of liquid 250,the layer of photoresist 252 is more likely to be properly developeduniformly across the whole surface of the IC wafer 202.

In addition to being directed toward the surface 203 of the IC wafer 202at an angle, the liquid streams 213, 215, 217, 219, 221, 223, and 225according to a preferred embodiment of the present invention aredispensed with relatively low pressure to further minimize back-splashand thus bubble formation within the layer of liquid 250.

The foregoing is by way of example only and is not intended to belimiting. For instance, the nozzle 204 of the present invention may beadvantageously practiced with more numerous nozzle passages thanillustrated in FIGS. 3, 4, and 7, as would be apparent to one ofordinary skill in the art from the description herein. In addition, theliquid dispensed with the nozzle 204 of the present invention may be anytype of solution used for fabrication of integrated circuits on the ICwafer aside from the example of developer solution for developing alayer of photoresist.

Furthermore, as will be understood by those skilled in the art, thestructures described herein may be made or used in the same wayregardless of their position and orientation. Accordingly, it is to beunderstood that terms and phrases such as “right,” “left,” “north,”“south,” “west,” and “east” as used herein refer to the relativelocation and orientation of various portions of the structures withrespect to one another, and are not intended to suggest that anyparticular absolute orientation with respect to external objects isnecessary or required.

The present invention is limited only as defined in the following claimsand equivalents thereof.

We claim:
 1. A nozzle system for dispensing liquid onto a surface of anIC (Integrated Circuit) wafer with minimized back-splash, the nozzlesystem comprising: a liquid chamber that fills up with said liquid to bedispensed onto said surface of said IC wafer that is spinning about acenter of said surface of said IC wafer; and a plurality of nozzlepassages, wherein each nozzle passage carries and directs said liquidfrom said liquid chamber toward said surface of said IC wafer to providea respective liquid stream from a respective location on said nozzle toa respective spot on said surface of said IC wafer as said IC wafer isspinning about said center; wherein a velocity vector at any location ofsaid surface of said IC wafer west of said center of said surface ofsaid IC wafer is in a north direction when said surface of said IC waferis spinning about said center in a clockwise direction; and wherein avelocity vector at any location of said surface of said IC wafer east ofsaid center of said surface of said IC wafer is in a south directionwhen said surface of said IC wafer is spinning about said center in aclockwise direction; and wherein a velocity vector at any location ofsaid surface of said IC wafer west of said center of said surface ofsaid IC wafer is in a south direction when said surface of said IC waferis spinning about said center in a counter-clockwise direction; andwherein a velocity vector at any location of said surface of said ICwafer east of said center of said surface of said IC wafer is in a northdirection when said surface of said IC wafer is spinning about saidcenter in a counter-clockwise direction; and wherein each nozzle passagedisposed west of said center of said surface of said IC wafer is angledtoward a north direction when said surface of said IC wafer is spinningabout said center in a clockwise direction, and wherein each nozzlepassage disposed east of said center of said surface of said IC wafer isangled toward a south direction when said surface of said IC wafer isspinning about said center in a clockwise direction, and wherein eachnozzle passage disposed west of said center of said surface of said ICwafer is angled toward a south direction when said surface of said ICwafer is spinning about said center in a counter-clockwise direction,and wherein each nozzle passage disposed east of said center of saidsurface of said IC wafer is angled toward a north direction when saidsurface of said IC wafer is spinning about said center in acounter-clockwise direction, such that said respective liquid streamfrom each nozzle passage is directed toward a velocity vector at saidrespective spot on said surface of said IC wafer where said respectiveliquid stream hits said surface of said IC wafer to minimize back-splashof said liquid from said surface of said IC wafer.
 2. The nozzle systemof claim 1, further comprising: developer solution contained within saidliquid chamber and dispensed on said surface of said IC wafer fordeveloping photoresist deposited on said surface of said IC wafer,wherein said minimized back-splash results in minimized bubble formationwithin said developer solution dispensed on said surface of said ICwafer.
 3. The nozzle system of claim 1, wherein said respective angle ofeach nozzle passage with respect to said surface of said IC wafer is45°.
 4. The nozzle system of claim 1, wherein said plurality of nozzlepassages are aligned in a linear configuration to face said surface ofsaid IC wafer across a diameter of said IC wafer.
 5. The nozzle systemof claim 4, wherein said IC wafer is spinning in a clockwise directionabout said center, and wherein a first plurality of nozzle passages arealigned in said linear configuration to a west of said center of said ICwafer with each of said first plurality of nozzle passages providing arespective liquid stream that is angled toward a north direction, andwherein a second plurality of nozzle passages are aligned in said linearconfiguration to a east of said center of said IC wafer with each ofsaid second plurality of nozzle passages providing a respective liquidstream that is angled toward a south direction.
 6. The nozzle system ofclaim 5, further comprising: a center nozzle passage disposed betweensaid first plurality of nozzle passages and said second plurality ofnozzle passages in said linear configuration, wherein said center nozzlepassage is perpendicular to said surface of said IC wafer above saidcenter of said IC wafer.
 7. The nozzle system of claim 4, wherein saidIC wafer is spinning in a counter-clockwise direction about said center,and wherein a first plurality of nozzle passages are aligned in saidlinear configuration to a west of said center of said IC wafer with eachof said first plurality of nozzle passages providing a respective liquidstream that is angled toward a south direction, and wherein a secondplurality of nozzle passages are aligned in said linear configuration toa east of said center of said IC wafer with each of said secondplurality of nozzle passages providing a respective liquid stream thatis angled toward a north direction.
 8. The nozzle system of claim 7,further comprising: a center nozzle passage disposed between said firstplurality of nozzle passages and said second plurality of nozzlepassages in said linear configuration, wherein said center nozzlepassage is perpendicular to said surface of said IC wafer above saidcenter of said IC wafer.
 9. A nozzle system for dispensing liquid onto asurface of an IC (Integrated Circuit) wafer with minimized back-splash,the nozzle system comprising: a liquid chamber that fills up with saidliquid to be dispensed onto said surface of said IC wafer that isspinning about a center of said surface of said IC wafer; and means forproviding a plurality of liquid streams, each liquid stream travelingfrom a respective location on said nozzle toward a respective spot onsaid surface of said IC wafer as said IC wafer is spinning about saidcenter; wherein a velocity vector at any location of said surface ofsaid IC wafer west of said center of said surface of said IC wafer is ina north direction when said surface of said IC wafer is spinning aboutsaid center in a clockwise direction; and wherein a velocity vector atany location of said surface of said IC wafer east of said center ofsaid surface of said IC wafer is in a south direction when said surfaceof said IC wafer is spinning about said center in a clockwise direction;and wherein a velocity vector at any location of said surface of said ICwafer west of said center of said surface of said IC wafer is in a southdirection when said surface of said IC wafer is spinning about saidcenter in a counter-clockwise direction; and wherein a velocity vectorat any location of said surface of said IC wafer east of said center ofsaid surface of said IC wafer is in a north direction when said surfaceof said IC wafer is spinning about said center in a counter-clockwisedirection; and wherein each liquid stream directed to a location of saidsurface of said IC wafer disposed west of said center of said surface ofsaid IC wafer is angled toward a north direction when said surface ofsaid IC wafer is spinning about said center in a clockwise direction,and wherein each liquid stream directed to a location of said surface ofsaid IC wafer disposed east of said center of said surface of said ICwafer is angled toward a south direction when said surface of said ICwafer is spinning about said center in a clockwise direction, andwherein each liquid stream directed to a location of said surface ofsaid IC wafer disposed west of said center of said surface of said ICwafer is angled toward a south direction when said surface of said ICwafer is spinning about said center in a counter-clockwise direction,and wherein each liquid stream directed to a location of said surface ofsaid IC wafer disposed east of said center of said surface of said ICwafer is angled toward a north direction when said surface of said ICwafer is spinning about said center in a counter-clockwise direction,such that each liquid stream is directed toward a velocity vector atsaid respective spot on said surface of said IC wafer where said liquidstream hits said surface of said IC wafer to minimize back-splash ofsaid liquid from said surface of said IC wafer.
 10. The nozzle system ofclaim 9, further comprising: developer solution contained within saidliquid chamber and dispensed on said surface of said IC wafer fordeveloping photoresist deposited on said surface of said IC wafer,wherein said minimized back-splash results in minimized bubble formationwithin said developer solution dispensed on said surface of said ICwafer.
 11. The nozzle system of claim 9, wherein said respective angleof a liquid stream with respect to said surface of said IC wafer is 45°.